The surge in Uniswap v2 pools on Layer 2 (L2) networks like Optimism, Arbitrum, and Polygon is indeed an interesting development in the decentralized finance (DeFi) space. The key drivers you mentioned—scalability, lower fees, and an improved user experience—are crucial factors contributing to this shift. Here’s a breakdown of each:

Scalability: Ethereum, despite its dominance, has been known for its congestion issues, leading to high transaction fees and slower processing times during peak periods. Layer 2 solutions address this by handling transactions off the main Ethereum chain, allowing for a much higher throughput. This is particularly beneficial for DeFi applications like Uniswap, which require fast and frequent transactions.

Lower Fees: One of the main advantages of L2 networks is their ability to drastically reduce gas fees. Since transactions are batched before being settled on Ethereum, the overall cost per transaction is lower. This makes participating in Uniswap v2 pools more accessible, especially for smaller investors who might be deterred by high fees on the main chain.

Improved User Experience: Faster transaction times and lower costs naturally lead to a better user experience. This is essential in DeFi, where the ability to quickly and cheaply execute trades can significantly impact a user's profitability and overall satisfaction.

The proliferation of these pools on L2 solutions not only signifies a maturing of the Uniswap ecosystem but also highlights the broader trend towards more scalable and user-friendly blockchain environments. This could potentially lead to greater adoption of DeFi technologies and more innovative applications in the future.